Hello.I ordered this 3.3V-12V In / +-15V Out Dual Power Step up converter to power my preamps from USB or batteries. Can i apply the K-multiplier at the output of step up converter?What modifications are needed for low drop K-multiplier supposing max output current wont exceed 100ma per rail?

If you want to add an inductor, most 5uH inductors are pretty good at blocking the upper end of SMPS noise. But they also tend to resonate with your supply lytics in the audio band. IE the same problem as lm317/337 regulators.

But I'd want to put an inductor or some sorta filter in between, personally.

I was reading the page about K-multiplier The K Multiplier and there is a point that states:

''This regulator exhibits diodic output impedance. This means output impedance decreases with increased loading. The opposite is also true, which is why this circuit should NEVER be used with loads less then 25mA.''

My preamp draws about 18ma per rail.Should the circuit of K-multiplier be modified?